This paper highlights the importance of rock mechanical studies for improved recovery of hydrocarbons from sandstone reservoirs. In recent times the advancements in rock mechanics have been increasingly applied in reservoirs with intermediate rock strength posing potential sanding problem and low permeability ones where hydraulic fracturing is often necessary. The petroleum related rock mechanical studies can provide significant improvements in the following areas: (a) optimization or rate of penetration (ROP) and orientation of deviated/horizontal wells; (b) prediction of maximum sand-free production rate in friable or weakly consolidated sandstone reservoirs, thus avoiding costly sand control methods such as gravel pack, in-situ sand consolidation, etc.; (c) optimization of injection and production well completions and locations for successful EOR programs; (d) infill drilling and well completion to maximize hydrocarbon recovery; and (e) hydraulic fracturing design for well stimulation. Rock mechanics study basically focuses on the failure conditions in which many criteria have been stipulated in the literature, constitutive modeling which characterizes rock deformation under various conditions, and determination of in-situ stress field. A careful assessment of the existing methods as well as specialized studies are necessary for application to hydrocarbon reservoirs. We have developed sophisticated rock mechanics and well-bore model laboratories to determine rock mechanical parameters and simulate sanding under in-situ conditions of reservoir pressure and temperature. Data from extensive ultrasonic experiments performed on cores and dipole acoustic logs proved useful in further characterizing reservoir rock behaviour. It is believed that carefully preserved cores provide the best representation of the formation from which they are withdrawn. Also, it is important to use the multi-stage rather than the single-stage triaxial testing in order to maximize the number of rock mechanical parameters from a single core. Wellbore stability problems are being revisited, along with in-situ stress field determination to optimize drilling and well stimulation. This trend is expected to continue beyond 2000 ad, with emphasis on experimental work and field applications.
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